Robotics has found a well accepted role in surgical procedures, particularly in laparoscopic procedures where arms can now be used with remote manipulation by a surgeon with direct visual feedback from the laparoscope to dissect, suture, tie, and perform complex procedures in the cardiac, thoracic, and abdominal spaces. Current robotic technology, however, is unsuitable for neurosurgical microsurgery, because of the large working space that is required for the robots, and the fact that the robots were not designed for the tasks that neurosurgeons normally need to do. This grant aims to develop a new class of "micro-robots" to bring the advantages of robotics and minimally-invasive techniques to neurosurgery. Phase II will continue development of steerable micro-robots that could be accurately directed by the neurosurgeon to locations in the brain via a number of entry points. During Phase I, micro-robot prototypes were successfully tested, and requirements for neurosurgical micro-robots were identified. In Phase II, prototypes will be developed and tested with phantoms to address a critical subset of these requirements: (1) sufficient miniaturization and degrees of freedom to allow conformance to five envisioned neurosurgical corridors, (2) safe levels of heat exposure to surrounding tissue, and (3) ability to advance or withdraw along neurosurgical corridors without colliding with surrounding tissue. The final study of the project will include animal studies, in which neurosurgeons on the project team will employ prototypes to navigate five pre-defined neurosurgical corridors. This is a necessary critical step to proving the value of the envisioned micro-robots in neurosurgery. Close collaboration throughout the project between the engineering team at Infoscitex and the neurosurgical clinical team at Children's Hospital Boston, will ensure that the design and testing move in the direction of most clinical utility.